1. Technical Field
This invention relates to an automatic washing device. More particularly, this disclosure relates to a device for automatically washing hands that uses fluidic oscillators.
2. Description of Related Art
The cleansing of objects, in particular as it relates to the washing of human and animal body parts and skin for the purpose of reducing pathogens that may be transmitted to other objects or parties, can be particularly useful to the medical, surgical and food handling communities. The ability to remove pathogens such as, for example, both transient Escherichia coli (E. coli), Salmonella and resident Staphylococcus aureus pathogens can reduce the transmittal of such bacteria. Transient micro-organisms are generally found on the surface of the skin and are picked up either through the air or by contact with a physical object. For example, the transient micro-organisms may be acquired by handling of raw meats and from previously contaminated surfaces and are generally readily washed off by any number of washing techniques. The resident microorganisms found embedded in the pores and folds of the skin and tissues may be more difficult to remove than from exposed surfaces. Fast food establishments are particularly prone to passing on such pathogens because large quantities of food are handled and served to the public and because of the lack of adequate training and education in hygiene required of food handling personnel.
The critical care of injured or wounded personnel can be improved based on the degree to which pathogens, and non-pathogens that can become pathogenic in the wound environment, can be eliminated from wounds prior to their being operated on, consequently minimizing the incidence of sepsis, infection, and disease. Until the 20th century many war deaths could be attributed to lack of sanitation and infection of, often, non-critical wounds.
Conventional scrubbing of skin, for example with cloths or brushes and soaps (both ordinary and antibacterial), is only moderately effective when a short procedure, such as is normally employed by marginally dedicated people, is used. Typically, about 50 percent removal occurs. Surgical scrubs, which may last as long as 5-15 minutes, depending on the diligence and experience of the personnel, may remove as much as 90-98 percent of the transient micro-organisms, but very few, if any, of the resident micro-organisms. Frequent scrubbing can result in “dish-pan-hands” syndrome, redness, irritation and epidermal loss, which is associated with abrasion as well as increased sensitivity to chemicals when the chemicals are forcibly scrubbed on the skin. Moreover, considerable time is consumed in thorough hand washing. When an 8 minute scrub is required even before a short procedure, this can limit the number of procedures that can be conducted during any given day. Automatic hand washing devices can improve the efficacy of the washing process and also reduce the time to achieve removal of pathogens as compared to manual washing.
Some automatic hand washers use nozzles to deliver fluids to clean the skin. The nozzles may be mechanical or electrical. A nozzle takes a steady input stream of fluid at a certain pressure and delivers a steady stream of fluid for cleansing at the same or different pressure. A Fluidic oscillator also may be mechanical or electrical. A fluidic oscillator takes a steady input stream of fluid at a certain pressure and delivers the fluid for cleansing at the same or different pressure in a sweeping action. However, a fluidic oscillator is distinguished from a nozzle in that the fluidic oscillator can deliver a pulsatile output stream of fluid swept in a fan shaped spray.
Pulsating jets of water that pulse at a frequency that is in resonance with the dynamic response of the human epidermis, about 20-25 Hz, can cause the skin to resonantly vibrate wherein the pores, ridges and crevices of the skin alternately expand and contract in such a way as to loosen resident pathogens as well as embedded oils, greases, and dirt/solid particles. High pressure (e.g., in the range of 50-80 psi) water jets can flush the loosened matter away while depositing antibacterial chemicals as desired, in effect scrubbing the dermis without the abrasive action of brushes.